"... P2P file downloading and streaming have already become very popular Internet applications. These systems dramatically reduce the server loading, and provide a platform for scalable content distribution, as long as there is interest for the content. P2P-based video-on-demand (P2P-VoD) is a new challe ..."

P2P file downloading and streaming have already become very popular Internet applications. These systems dramatically reduce the server loading, and provide a platform for scalable content distribution, as long as there is interest for the content. P2P-based video-on-demand (P2P-VoD) is a new challenge for the P2P technology. Unlike streaming live content, P2P-VoD has less synchrony in the users sharing video content, therefore it is much more difficult to alleviate the server loading and at the same time maintaining the streaming performance. To compensate, a small storage is contributed by every peer, and new mechanisms for coordinating content replication, content discovery, and peer scheduling are carefully designed. In this paper, we describe and discuss the challenges and the architectural design issues of a large-scale P2P-VoD system based on the experiences of a real system deployed by PPLive. The system is also designed and instrumented with monitoring capability to measure both system and component specific performance metrics (for design improvements) as well as user satisfaction. After analyzing a large amount of collected data, we present a number of results on user behavior, various system performance metrics, including user satisfaction, and discuss what we observe based on the system design. The study of a real life system provides valuable insights for the future development of P2P-VoD technology.

...SA. Copyright 2008 ACM 978-1-60558-175-0/08/08 ...$5.00. 1. INTRODUCTION AND CONTRIBUTION The effectiveness of using the P2P approach for content distribution has been proven by many deployed systems =-=[1, 2, 3, 4, 9, 21]-=-. These P2P systems offer many different services. One type of service is P2P file downloading, for example implemented by BitTorrent [9] and Emule [1]. When a file is downloaded by many users, these ...

"... Abstract—YouTube has become the most successful Internet website providing a new generation of short video sharing service since its establishment in early 2005. YouTube has a great impact on Internet traffic nowadays, yet itself is suffering from a severe problem of scalability. Therefore, understa ..."

Abstract—YouTube has become the most successful Internet website providing a new generation of short video sharing service since its establishment in early 2005. YouTube has a great impact on Internet traffic nowadays, yet itself is suffering from a severe problem of scalability. Therefore, understanding the characteristics of YouTube and similar sites is essential to network traffic engineering and to their sustainable development. To this end, we have crawled the YouTube site for four months, collecting more than 3 million YouTube videos ’ data. In this paper, we present a systematic and in-depth measurement study on the statistics of YouTube videos. We have found that YouTube videos have noticeably different statistics compared to traditional streaming videos, ranging from length and access pattern, to their growth trend and active life span. We investigate the social networking in YouTube videos, as this is a key driving force toward its success. In particular, we find that the links to related videos generated by uploaders ’ choices have clear small-world characteristics. This indicates that the videos have strong correlations with each other, and creates opportunities for developing novel techniques to enhance the service quality. I.

...is to utilize the peer-to-peer (P2P) technique, which has been quite successful in supporting largescale live video streaming (e.g., PPLive and CoolStreaming) and on-demand streaming (e.g., GridCast) =-=[30]-=-, [31]. Yet the unique characteristics of YouTube videos make P2P delivery quite challenging. In particular, the ultra large quantity of the videos and the short length of each video render the per-vi...

"... Abstract — BitTorrent (BT) in the last years has been one of the most effective mechanisms for P2P content distribution. Although BT was created for distribution of time insensitive content, in this work we try to identify what are the minimal changes needed in the BT’s mechanisms in order to suppor ..."

Abstract — BitTorrent (BT) in the last years has been one of the most effective mechanisms for P2P content distribution. Although BT was created for distribution of time insensitive content, in this work we try to identify what are the minimal changes needed in the BT’s mechanisms in order to support streaming. The importance of this capability is that the peer will now have the ability to start enjoying the video before the complete download of the video file. This ability is particularly important in highly polluted environments, since the peer can evaluate the quality of the video content early and thus preserve its valuable resources. In a nutshell, our approach gives higher download priority to pieces that are close to be reproduced by the player. This comes in contrast to the original BT protocol, where pieces are downloaded in an out-of-order manner based solely on their rareness. In particular, our approach tries to strike the balance between downloading pieces in: (a) playing order, enabling smooth playback, and (b) the rarest first order, enabling the use of parallel downloading of pieces. In this work, we introduce three different Piece Selection mechanisms and we evaluate them through simulations based on how well they deliver streaming services to the peers. I.

... work we show that by requesting pieces in a rarest first manner within a small window of the file, we can guarantee diversity of pieces as well as high QoS. Another interesting work is CoolStreaming =-=[11]-=-. CoolStreaming, uses a data-centric design of an overlay network. Similar to our work, they introduce the notion of a sliding time window from which peers select to download a piece. The decision of ...

"... Peer-to-peer technologies have proved to be effective for various bandwidth intensive, large scale applications such as file-transfer. For many years, there has been tremendous interest in academic environments for live video streaming as another application of P2P. Recently, a number of new commerc ..."

Peer-to-peer technologies have proved to be effective for various bandwidth intensive, large scale applications such as file-transfer. For many years, there has been tremendous interest in academic environments for live video streaming as another application of P2P. Recently, a number of new commercial scale video streaming systems have cropped up. These systems differ from others in the type of content that they provide and attract a large number of users from across the globe. These are proprietary systems and very little is known about their architecture and behavior. This study is one of the first of its kind to analyze the performance and characteristics of P2P live streaming applications. In particular, we analyze PPLive and SOPCast, two of the most popular systems in this class. In this paper, we (1) present a framework in which to analyze these P2P applications from a single observable point, (2) analyze control traffic to present a probable operation model and (3) present analysis of resource usage, locality and stability of data distribution. We conclude that P2P live streaming has an even greater impact on network bandwidth utilization and control than P2P file transfer applications.

"... Abstract — There have been tremendous efforts and many technical innovations in supporting real-time video streaming in the past two decades, but cost-effective large-scale video broadcast has remained an elusive goal. IP multicast represented the earlier attempt to tackle this problem, but failed l ..."

Abstract — There have been tremendous efforts and many technical innovations in supporting real-time video streaming in the past two decades, but cost-effective large-scale video broadcast has remained an elusive goal. IP multicast represented the earlier attempt to tackle this problem, but failed largely due to concerns regarding scalability, deployment, and support for higher level functionality. Recently, peer-to-peer based broadcast has emerged as a promising technique, which has been shown to be cost effective and easy to deploy. This new paradigm brings a number of unique advantages such as scalability, resilience and also effectiveness in coping with dynamics and heterogeneity. While peer-to-peer applications such as file download and voice over IP have gained tremendous popularity, video broadcast is still in its early stages and its full potential remains to be seen. This article reviews the state-of-the-art of peer-to-peer Internet video broadcast technologies. We describe the basic taxonomy of peer-to-peer broadcast and summarize the major issues associated with the design of broadcast overlays. We closely examine two approaches, namely, tree-based and data-driven, and discuss their fundamental trade-off and potential for large-scale deployment. Finally, we outline the key challenges and open problems, and highlight possible avenues for future directions. I.

...ity. C. Approaches for Overlay Construction A large number of proposals have emerged in recent years for peer-to-peer video broadcast [4]–[6], [8], [9], [14], [16], [19], [22], [27]–[29], [36], [37], =-=[41]-=-, [43]. While these proposals differ on a wide-range of dimensions, in this article, we focus on the approach taken towards the overlay structure used for data dissemination. In particular, the propos...

"... Abstract — We consider the problem of broadcasting a live stream of data in an unstructured network. The broadcasting problem has been studied extensively for edge-capacitated networks. We give the first proof that whenever demand λ + ε is feasible for ε>0, a simple local-control algorithm is sta ..."

Abstract — We consider the problem of broadcasting a live stream of data in an unstructured network. The broadcasting problem has been studied extensively for edge-capacitated networks. We give the first proof that whenever demand λ + ε is feasible for ε&gt;0, a simple local-control algorithm is stable under demand λ, and as a corollary a famous theorem of Edmonds. We then study the node-capacitated case and show a similar optimality result for the complete graph. We study through simulation the delay that users must wait in order to playback a video stream with a small number of skipped packets, and discuss the suitability of our algorithms for live video streaming. I.

... trees [1]–[5]. The broadcast problem is at the core of every content distribution system. In particular, it is of great interest to current live streaming distribution systems, such as CoolStreaming =-=[6]-=-, PPLive [7], SplitStream [8], and others. Those systems either construct the overlay topology in such a way to easy packet scheduling, and in doing so reduce the network efficiency by not optimally u...

"... Abstract — In information theory, it has been shown that network coding can effectively improve the throughput of multicast communication sessions in directed acyclic graphs. More practically, random network coding is also instrumental towards improving the downloading performance in BitTorrent-like ..."

Abstract — In information theory, it has been shown that network coding can effectively improve the throughput of multicast communication sessions in directed acyclic graphs. More practically, random network coding is also instrumental towards improving the downloading performance in BitTorrent-like peerto-peer content distribution sessions. Live peer-to-peer streaming, however, poses unique challenges to the use of network coding, due to its strict timing and bandwidth constraints. In this paper, we revisit the complete spectrum in the design space of live peer-to-peer streaming protocols, with a sole objective of taking full advantage of random network coding. We present R 2, our new streaming algorithm designed from scratch to incorporate random network coding with a randomized push algorithm. R 2 is designed to improve the performance of live streaming in terms of initial buffering delays, resilience to peer dynamics, as well as reduced bandwidth costs on dedicated streaming servers, all of which are beyond the basic requirement of stable streaming playback. On an experimental testbed consisting of dozens of dual-CPU cluster servers, we thoroughly evaluate R 2 with an actual implementation, real network traffic, and emulated peer upload capacities, in comparisons with a typical live streaming protocol (both without and with network coding), representing the current state-of-the-art in real-world streaming applications. Index Terms — peer-to-peer networks, multimedia streaming, network coding I.

...r-to-peer networks, multimedia streaming, network coding I. INTRODUCTION The peer-to-peer communication paradigm has been successfully used in live multimedia streaming applications over the Internet =-=[1]-=-. The essential advantage of live peer-topeer streaming is to dramatically increase the number of peers a streaming session may sustain with several dedicated streaming servers. Intuitively, as partic...

"... User Generated Content has become very popular since the birth of web services such as YouTube allowing the distribution of such user-produced media content in an easy manner. YouTube-like services are different from existing traditional VoD services because the service provider has only limited con ..."

User Generated Content has become very popular since the birth of web services such as YouTube allowing the distribution of such user-produced media content in an easy manner. YouTube-like services are different from existing traditional VoD services because the service provider has only limited control over the creation of new content. We analyze how the content distribution in YouTube is realized and then conduct a measurement study of YouTube traffic in a large university campus network. The analysis of the traffic shows that: (1) No strong correlation is observed between global and local popularity; (2) neither time scale nor user population has an impact on the local popularity distribution; (3) video clips of local interest have a high local popularity. Using our measurement data to drive trace-driven simulations, we also demonstrate the implications of alternative distribution infrastructures on the performance of a YouTube-like VoD service. The results of these simulations show that client-based local caching, P2P-based distribution, and proxy caching can reduce network traffic significantly and allow faster access to video clips. Keywords: Measurement study, Peer-to-peer, Content distribution, Caching 1.

"... Abstract — Most of the real deployed peer-to-peer streaming systems adopt pull-based streaming protocol. In this paper, we demonstrate that, besides simplicity and robustness, with proper parameter settings, when the server bandwidth is above several times of the raw streaming rate, which is reasona ..."

Abstract — Most of the real deployed peer-to-peer streaming systems adopt pull-based streaming protocol. In this paper, we demonstrate that, besides simplicity and robustness, with proper parameter settings, when the server bandwidth is above several times of the raw streaming rate, which is reasonable for practical live streaming system, simple pull-based P2P streaming protocol is nearly optimal in terms of peer upload capacity utilization and system throughput even without intelligent scheduling and bandwidth measurement. We also indicate that whether this near optimality can be achieved depends on the parameters in pull-based protocol, server bandwidth and group size. Then we present our mathematical analysis to gain deeper insight in this characteristic of pull-based streaming protocol. On the other hand, the optimality of pull-based protocol comes from a cost-tradeoff between control overhead and delay, that is, the protocol has either large control overhead or large delay. To break the tradeoff, we propose a pull-push hybrid protocol. The basic idea is to consider pull-based protocol as a highly efficient bandwidthaware multicast routing protocol and push down packets along the trees formed by pull-based protocol. Both simulation and real-world experiment show that this protocol is not only even more effective in throughput than pull-based protocol but also has far lower delay and much smaller overhead. And to achieve near optimality in peer capacity utilization without churn, the server bandwidth needed can be further relaxed. Furthermore, the proposed protocol is fully implemented in our deployed GridMedia system and has the record to support over 220,000 users simultaneously online. Index Terms — p2p streaming, pull-based, pull-push hybrid, capacity utilization, throughput, delay I.

...ch and Development Plan of China (863) under Grant No. 2006AA01Z321, the HKUST Nansha Research Fund NRC06/07.EG01, the HKUST RPC06/07.EG05, and CERG 622407. protocol are its simplicity and robustness =-=[4]-=-, [5]. In peer-topeer streaming study, there are a lot of efforts made on enhancing the throughput of a P2P overlay. The maximum throughput that a P2P overlay can achieve is the total upload capacity ...

... of uncontrolled environments, e.g., the public Internet. 1. INTRODUCTION Over the past five years, there has been considerable research in the use of peer-to-peer networks for distributing both live =-=[6, 26, 20, 19]-=- and stored [7, 2] video. In such systems, peer interest plays the central role in content transmission and storage - a peer pulls content only if the content is of interest. Once pulled content has b...